Plaster lath



J. F. MAKOWSKI PLASTER LATH Original Filed Dec. 25, 1922 INVENTOR JJ'? Mil/cocoa?! Z TEQNEY Patented Feb. 3, 1925,

UNITED STATES I 1,524,939 PATENT OFFICE.

JOHN F. MAKOWSKI, OF STOCKTON, CALIFORNIA, ASSIGNOR TO CALIFORNIA CEDAR PRODUCTS COMPANY, OF STOCKTON, CALIFORNIA.

.ILASTER LATH.

Continuation of application Serial No; 608,595, filed December 23, 1922. This application filed March 22, 1924. Serial No. 701,057.

To all whom it may concern:

Be it known that I, JOHN F. MAKowsKI,

a citizen of the United States, residing at Stockton, county of San J oaquin, State of I California, have invented certain new and useful Improvements in Plaster Lathe; and

I do declare the following to be a full, clear,

and exact description of the same, reference being had to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this appllcation.

This invention relates to the building art and particularly to plaster wall c onstr uc tion, this application being a continuation of my application, Serial N 0. 608,595, filed December 23, 1922.

The main object of the invention is to produce a lath or plaster board to be used as a substitute for wooden or metal lath heretofore commonly used in the plastering art.

The ideal plaster lath is one which can be manufactured at a reasonable price; will present a smooth even surface; Wlll. function as an efficient bond for'the plaster or other plastic material; and which will not be subject: to expansion, contraction, cracking or sagging, so that the plastered surface will remain smooth and true without cracking or flaking ofi'.

Much cllort has been put forward by inventors to this end and so far it has been found that the one coming nearest to giving the desired result has been a plaster lath having as its base a smooth sheet of wall board of that type wherein a center core of gypsum plaster, and a. filler such as sawdust or the like, is interposed between and adhered to surface sheets of strong paper such as chip board or the like. With this smooth board as a base many difierent types of mechanical plaster keys or bonds have been formed on its face such as protuberances projecting therefrom, or recesses. depressions or perforations formed therein.

There has been one thing however which has acted tocause this type of plaster lath to be more or less unsatisfactory and that is the fact that in many cases when the wet plaster is applied over the same the moisture therein is apt to saturate the paper covering of the wall board, or itsplastic core, before the plaster has had time todry and harden and set. When this occurs the sur face paper loses its tensile strength and is and I claim to have solved it and tohave perfected a plaster lath which Will have the several advantages derived from the use of wall board of the type above set forth and with none of the disadvantages of the kind described.

The thing which I conceived to .be necessary to make the lath a success was to keep the moisture of the plaster out of the base board while the plaster was drying, hardening and setting and at the same time provide a perfect bond between the two at all times.

To keep the moisture out during the time noted I conceived of the idea of treating the surface paper with an element which would retard the permeation of moisture therethrough for a period of time suflicient to allow the outer plastered surface to dry, harden and set. This would hold the moisture not only out of the paper but would also keep it out of the plastic core of the wall board if I maintained the surface paper in smooth unbroken condition. As most of the previously known plaster laths of this type have the mechanical key or bond for the plaster formed thereon by breaking the paper to make depressions or protuberances, I was compelled, in order to render the use of my treated paper practical, to devise a key or bond which would be entirely outside of the unbroken and treated surface paper of the base and yet adhered thereto with a. tenacity to carry the weight of the plaster to be adhered llthereto.

The figure 011 the drawings is a perspective View of a section of my improved plaster lath showing plaster adhered to a portion thereof.

Referring now more particularly to the characters of reference on the drawings, the numeral 1 designates the internal core of the wall board base which core is made prefers.

' for a period of time sufficient to allow the surface coating of plaster 6, to be adhered thereto, to dry, harden and set without the moisture therein saturating the paper or. plastic core. This treatment may-be by incorporation ofthe element'itself in the paper in manufacture or by sizing after the board is made. The element used will be rosin or other known retardents.

- The paper being thus treated the next necessary step is to arrange a mechanical key on the outer surface thereof. Preferably I. use finely divided mineral fragments i adhered to the paper by an adhesive which must of course be essentially insoluble in W order that the same will be also unaffected 30' by the moisture in the plaster 6 when the same is first adheredthereto.

I have done vast experimenting to find the proper adhesive elementfor 'this last noted purpose and have several co-pending applications covering same, each of them having certain other properties essential to the manufacture of a commercially success- I ful lath. F or the purpose of this application I disclose this adhesive shown on the drawing at 5, as a composition of casein, lime and china clay or any similar diatomaceous earth. In this composition the casein is the insoluble element, the lime acting as atemporary solvent for the same, and the diatomaceous earth giving the necessary body to the composition.

Such an insoluble adhesive composition could also be so compounded as to act to treat the surface paper of the wall board to retard permeation thereof by moisture. \Vhen this was done the paper when first adhered to the plastic core would not need to be anything but plain untreated chip board or the like. A larger quantity of the adhesive composition would then have to be used however so that it could thoroughly impregnate the paper and at the same time have body enou h to allow the mineral fragments to tenaclously adhere thereto or in itself be of a thickness necessary to retard the permeation of moisture, through to the paper, for the requisite period of time herein indicated.

I must lay stress on the fact that the adhesive between the mechanical bond and the surface sheet of paperof the base board must be insoluble in any event, otherwise when the wet plaster was spread over the lath this adhesive woulddissolve and slide off the surface and the entire utility of the lath would be destroyed.

lVhile I have herein indicated the mechanical key or bond surface as preferably provided by the'finely dividedgravel "still in practice suc-h'may be provided in perhaps many other ways. It might even, for instance, be provided by placing a relatively thick coat of insoluble material over the surface of the base board and then scarifying it to provide. a rough surface to act as such key or bond. j

From' the foregoing description it will apparent that I have produced a plaster lath which will permit of the useofa wall board base, with its many advantages, at -the same time avoiding the disadvantages heretofore encountered.

Having thus described my invention what I claim as new and useful and desire to secure by Letters Patent is:

l. A plaster lath clomprising a plastic base united to a surface sheet of paper or the like in superficial contact therewith, such paper being treated to retard its permeation by moisture, and a plaster key or bond arranged on the outer face of thepaper.

2. A plaster lath comprising a plastic base united to an unbroken surface sheet of paper or the like in superficial contact therewith, such paper being treatedto retard its permeation by moisture, and a plaster key .or bond arranged on the outer face of the paper. 7

3. A plaster lath comprising a plastic base united to a surface sheet of paper or the like in superficial contact therewith, such paper being treated to retard its permeation by moisture, an insoluble coating on the outer surface of the paper, and a plaster key or bond formed in such insoluble coating.

4. A plaster lath com1.)rising a plastic base united to a surface sheet of paper or the like in superficial contact therewith, such paper being treated to retard its permeation by moisture, an insoluble coatin on 'the outer surface of the paper, and nely divided material adhered to such coating to form a plaster bond or key.

5. A plaster lath comprising a plastic base united to a surface sheet of paper or the like in superficial contact therewith, and a plaster key or bond formed onthe outer surface of such sheet of paper, the paper being treated to retard its permeation by moisture, from the plaster applied to such key or bond, for the period of time required for such plaster to harden and set.

6. A plaster lath comprising a plastic base united to a surface sheet of paper or superficial contact therewith, a coating of l the like in superficial contact therewith, and surfacing material on the outer face of such a plaster key or bond formed on the outer paper sheet consisting essentiallyof casein surface of such sheet of paper, and means and a body material, and a plaster key or whereby, when plaster is applied thereto, bond formed in such coating. v I the moisture in such plaster will be excluded In testimony whereof I aflix my signa- 1 from permeating the paper or plastic base. ture. V

7. A plaster lath comprising a plastic base united to a surface sheet of paper in ,JOHN F. MAKOWSKI. 

